Modeling seasonal redox dynamics and the corresponding fate of the pharmaceutical residue phenazone during artificial recharge of groundwater

Reactive multicomponent transport modeling was used to investigate and quantify the factors that affect redox zonation and the fate of the pharmaceutical residue phenazone during artificial recharge of groundwater at an infiltration site in Berlin, Germany. The calibrated model and the corresponding sensitivity analysis demonstrated thattemporal and spatial redox zonation at the study site was driven by seasonally changing, temperature-dependent organic matter degradation rates. Breakthrough of phenazone at monitoring wells occurred primarily during the warmer summer months, when anaerobic conditions developed. Assuming a redox-sensitive phenazone degradation behavior the model results provided an excellent agreement between simulated and measured phenazone concentrations. Therefore, the fate of phenazone was shown to be indirectly controlled by the infiltration water temperature through its effect on the aquifer's redox conditions. Other factors such as variable residence times appeared to be of less importance.     

Characterizing the redox status in three different forested wetlands with geochemical data

Biogeochemistry and regulation of redox processes in wetlands and especiallytheir source sink functions regarding sulfur, nitrogen, iron, and alkalinity are still poorly understood and become increasingly important in a world of global change. We investigated three forested wetlands within the Lehstenbach catchment (Fichtelgebirge, Northeastern Bavaria, Germany) differing in their degree of water saturation, vegetation, and availability of iron with stable sulfur analysis as well as geochemical analysis (iron, nitrate, sulfate, and oxygen contents in soil solutions and groundwater). Results indicated considerable nitrate, sulfate, and iron reduction rates bound to high spatial and temporal heterogeneity at all three sites. Sites differed significantly regarding their oxygen saturation and their dynamics of sulfur and iron reduction. The sequential reduction chain did not seem an applicable concept to describe redox dynamics at micro- (cm(2)) or mesoscale (m(2)) because of (1) high small-scale heterogeneity and (2) an absence of clear relationships between redox indicative parameters. The latter might be caused by redox processes occurring simultaneously at the investigated spatial and temporal scales. However, a tendency toward exclusive relationships between oxygen and iron, nitrate and iron, and delta34S with oxygen, nitrate, and sulfate indicated that the sequential reduction chain might be a suitable modeling concept for macroscale (km(2)) investigations with large sample numbers.     

MicroRNA-449a Inhibits Triple Negative Breast Cancer by Disturbing DNA Repair and Chromatid Separation

Chromosomal instability (CIN) can be a driver of tumorigenesis but is also a promising therapeutic target for cancer associated with poor prognosis such as triple negative breast cancer (TNBC). The treatment of TNBC cells with defects in DNA repair genes with poly(ADP-ribose) polymerase inhibitor (PARPi) massively increases CIN, resulting in apoptosis. Here, we identified a previously unknown role of microRNA-449a in CIN. The transfection of TNBC cell lines HCC38, HCC1937 and HCC1395 with microRNA-449a mimics led to induced apoptosis, reduced cell proliferation, and reduced expression of genes in homology directed repair (HDR) in microarray analyses. EME1 was identified as a new target gene by immunoprecipitation and luciferase assays. The reduced expression of EME1 led to an increased frequency of ultrafine bridges, 53BP1 foci, and micronuclei. The induced expression of microRNA-449a elevated CIN beyond tolerable levels and induced apoptosis in TNBC cell lines by two different mechanisms: (I) promoting chromatid mis-segregation by targeting endonuclease EME1 and (II) inhibiting HDR by downregulating key players of the HDR network such as E2F3, BIRC5, BRCA2 and RAD51. The ectopic expression of microRNA-449a enhanced the toxic effect of PARPi in cells with pathogenic germline BRCA1 variants. The newly identified role makes microRNA-449a an interesting therapeutic target for TNBC.     

Brain potential correlates of supraliminal contrast functions and defocus

In six subjects with normal corrected vision, perceived suprathreshold contrast of a sine‐wave grating pattern was assessed by an intermodal matching technique in combination with the method of ratio estimation. Vertical gratings were produced on an oscilloscope screen at spatial frequencies of 1.0, 2.0, 3.5, 5.0, 9.0 and 15.0 cycles per degree (c/deg) and at contrast levels between 0.03 and 0.55. Steady‐state visual evoked potentials (VEP) were recorded from the occiput to phase‐reversing gratings of the same spatial frequency and contrast range. A linear relation was found in logarithmic coordinates between perceived and physical contrast and between VEP amplitude and physical contrast. The slopes varied with spatial frequency and were steeper at low and high spatial frequencies than in the intermediate range for both subjective contrast and VEP.

In a second group of six subjects, the effect of retinal image defocus (myopia) on the psychophysical power functions was determined by placing spherical plus lenses in front of the eyes. A marked change in slope was obtained with blurred stimuli, and this effect was more pronounced with an increase in spatial frequency. Power transformations can thus be induced by neural and optical factors. Growth rate of supraliminal response functions seems to be inversely related to detection threshold of sensory systems.     

Critical evaluation and optimization of the thermodynamic properties and phase diagrams of the MnO-TiO2, MgO-TiO2, FeO-TiO2, Ti2O3-TiO2, Na2O-TiO2, and K2O-TiO2 systems

All available thermodynamic and phase diagram data have been critically assessed for all phases in the MnO-TiO₂, MgO-TiO₂, FeO-TiO₂, Ti₂O₃-TiO₂, Na₂O-TiO₂, and K₂O-TiO₂ systems at 1 bar pressure from 298 K to above the liquidus temperatures. All reliable thermodynamic and phase diagram data have been simultaneously optimized to obtain, for each system, one set of model equations for the Gibbs energy of the liquid slag as a function of composition and temperature and equations for the Gibbs energies of all compounds as functions of temperature. The modified quasichemical model was used for the molten slag phases.     

Entrapped Molecule-Like Europium-Oxide Clusters in Zinc Oxide with Nearly Unaffected Host Structure

Nanocrystalline ZnO sponges doped with 5 mol% EuO_1.5 are obtained by heating metal–salt complex based precursor pastes at 200–900 °C for 3 min. X-ray diffraction, transmission electron microscopy, and extended X-ray absorption fine structure (EXAFS) show that phase separation into ZnO:Eu and c-Eu₂O₃ takes place upon heating at 700 °C or higher. The unit cell of the clean oxide made at 600 °C shows only ≈0.4% volume increase versus undoped ZnO, and EXAFS shows a ZnO local structure that is little affected by the Eu-doping and an average Eu³⁺ ion coordination number of ≈5.2. Comparisons of 23 density functional theory-generated structures having differently sized Eu-oxide clusters embedded in ZnO identify three structures with four or eight Eu atoms as the most energetically favorable. These clusters exhibit the smallest volume increase compared to undoped ZnO and Eu coordination numbers of 5.2–5.5, all in excellent agreement with experimental data. ZnO defect states are crucial for efficient Eu³⁺ excitation, while c-Eu₂O₃ phase separation results in loss of the characteristic Eu³⁺ photoluminescence. The formation of molecule-like Eu-oxide clusters, entrapped in ZnO, proposed here, may help in understanding the nature of the unexpected high doping levels of lanthanide ions in ZnO that occur virtually without significant change in ZnO unit cell dimensions.     

Hydraulic classification of hydropeaking stages in a river reach

Hydropower is an important tool in the struggle for low-emission power production. In the Nordic countries, hydropower operating conditions are expected to change and work more in conjunction with intermittent power production. This in turn might increase the amount of hydropeaking events in the reaches downstream of hydropower plants. The current work investigates the influence of highly flexible, high-frequency hydropeaking on the hydrodynamics in the downstream reach. By quantifying four different dynamic stages in the study reach, the influence of the hydropeaking frequencies was investigated in the bypass reach of the Stornorrfors hydropower plant in the river Umeälven in northern Sweden. The hydrodynamics in the study reach were numerically modelled using the open source solver Delft3D. Eight different highly flexible future hydropeaking scenarios, varying from 12 to 60 flow changes per day, were considered. A method for identifying four hydropeaking stages—dewatering, dynamic, alternating and uniform —was introduced. The hydropeaking frequency directly decided the stage in most of the study reach. Furthermore, a Fourier analysis showed a significant difference between the stages and their corresponding power spectra. The classification of stages put forward in this work provides a novel, simple method to investigate the hydrodynamics due to hydropeaking in a river reach.